This type of force measuring device is disclosed, for example, in the British patent No. 2,133,880. In this device, a metal string is stretched between free ends of a pair of parallel cantilever members and a force to be measured is applied to the free end of one of these members. The tension of the string, which is functionally related to the magnitude of the applied force, also functionally relates to the inherent vibration frequency of the string. Therefore, if the vibration frequency is measured, the applied force can be calculated therefrom.
The tension of the metal string is also controlled by the spring constants of the cantilever members and the spring constants are generally influenced by the surrounding temperature. The string is provided with an initial tension by the repulsion of the slightly deflected cantilever members and this initial tension determines the zero reading of the device. Therefore, a change of the member temperature may result in an undesirable zero-point shift which in turn results in a measurement error.